Soft mode origin of charge ordering in superconducting kagome CsV3Sb5
Abstract Charge-density-wave (CDW) order and superconductivity coexist in the kagome metals AV 3 Sb 5 (A=K, Cs, Rb), raising fundamental questions about the mechanisms driving their intertwined phases. Here we combine high-resolution inelastic X-ray scattering with first-principles calculations to uncover the origin of CDW formation in CsV 3 Sb 5 . Guided by structure factor analysis, we identify a soft phonon mode along the reciprocal M - L direction, with the strongest effect at the L point, where the elastic scattering intensity also grows most rapidly upon cooling. First-principles calculations incorporating lattice anharmonicity and electron-phonon coupling reproduce these observations and establish a soft-mode instability at the L point as the driving mechanism of CDW formation. Despite the weakly first-order character of the transition, our results unambiguously demonstrate that the CDW in CsV 3 Sb 5 originates from a softened phonon, clarifying its microscopic origin and highlighting the central role of lattice dynamics in kagome metals.
Authors
- R. Heid (ORCID: https://orcid.org/0000-0002-2144-1417)
- Maia G. Vergniory (ORCID: https://orcid.org/0000-0001-7336-3062)
- Michael Merz (ORCID: https://orcid.org/0000-0002-7346-7176)
- Alfred Q. R. Baron (ORCID: https://orcid.org/0000-0002-5899-2116)
- Amir A. Haghighirad (ORCID: https://orcid.org/0000-0003-4723-4966)
- Ion Errea (ORCID: https://orcid.org/0000-0002-5719-6580)
- Philippa H. McGuinness (ORCID: https://orcid.org/0000-0001-5938-6452)
- A. N. Korshunov (ORCID: https://orcid.org/0000-0001-5929-6473)
- Mark Joachim Graf von Westarp (ORCID: https://orcid.org/0000-0003-4984-7926)
- S. M. Souliou (ORCID: https://orcid.org/0000-0001-9201-7392)
- M. Le Tacon (ORCID: https://orcid.org/0000-0002-5838-3724)
- Daisuke Ishikawa (ORCID: https://orcid.org/0000-0001-8353-3248)
- Manex Alkorta (ORCID: https://orcid.org/0009-0003-8109-9216)
- A. Bosak
- Fabian Henssler
Institutions
- Karlsruhe Institute of Technology (DE)
- Université de Sherbrooke (CA)
- University of the Basque Country (ES)
- European Synchrotron Radiation Facility (FR)
- Max Planck Institute for Solid State Research (DE)
- SPring-8 (JP)
- Regroupement Québécois sur les Matériaux de Pointe (CA)
- RIKEN Center for Biosystems Dynamics Research (JP)
- Material Physics Center (ES)
- Donostia International Physics Center (ES)
Publication Details
- Journal
- Nature Communications
- Published
- 2026-05-30
- DOI
- https://doi.org/10.1038/s41467-026-73662-4
- Primary Topic
- Topological Materials and Phenomena
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Deutsche Forschungsgemeinschaft
- European Synchrotron Radiation Facility
- Canada Excellence Research Chairs, Government of Canada
- Eusko Jaurlaritza
- Euskal Herriko Unibertsitatea
- Natural Sciences and Engineering Research Council of Canada
- RIKEN
- Agencia Estatal de Investigación